Electrical disconnect switches are well known in the prior art. An example of such an electrical disconnect switch is disclosed in U.S. Pat. No. 4,302,643 entitled "Fusible Switch" which is assigned to the same assignee as the present application, and is hereby incorporated by reference.
Electrical disconnect switches interrupt current flowing through an electrical circuit. Opaque covers have been provided for enclosing a switching mechanism within an enclosure and protect personnel against electrical arcing. However, when the disconnect switch is in the closed, or "ON," position the user can not open the cover and visually inspect the position of the current conducting blades. Without a viewing window, the user must turn "OFF" the switch and open the cover to visually inspect the blade position. In certain situations it is desirous to visually inspect the blade position while the switch is "ON".
A need, therefore, exists for an electrical disconnect switch that allows the user to visually inspect the position of the blades without opening the cover of the switch while the switch is in the "ON" position, yet will provide protection in the event of electrical arcing of the switch contacts.
One way of providing a transparent shield that allows users to visually inspect the position of the blades is shown in U.S. Pat. No. 4,110,584 entitled "Load Break Switch With Transparent Internal Shield." However, this design uses a transparent shield that is supported across the front of the switch contacts and is located inside the housing so that it will visually expose the contacts when the cover is open. The transparent shield shown in U.S. Pat. No. 4,110,584 is separate from the cover thus requiring the user to open the cover prior to visually inspecting the contacts or blades. It is desirous to provide a disconnect switch that would allow the user to visually inspect the blades without opening the switch cover as is required by the aforementioned patent.